A whistleblower filed a lawsuit today to force the federal government to halt operations at another massive BP oil platform in the Gulf of Mexico, alleging that BP never reviewed critical engineering designs for the operation and is therefore risking another catastrophic accident that could "dwarf" the company's Deepwater Horizon spill.

One key reason the Gulf oil spill has been so hard to stop is that BP was drilling so deep. Such deepwater drilling has been increasingly common -- but both BP and regulators seem to have been unprepared for the complications that can crop up.

At 5,000 feet, the BP's ruptured well continues to gush oil into the Gulf of Mexico.

When regulators at the Minerals Management Service had concerns about the safety equipment for offshore oil rigs, the agency did not impose stronger regulations and instead allowed industry to police itself, according to two pieces in The New York Times and The Wall Street Journal today.

The agency has been scrutinized for its role in the massive BP oil spill in the Gulf of Mexico, particularly for failing to follow up on concerns it had -- several years before the BP incident -- about equipment that should have stopped the spill but did not.

BP Oil Spill: Is Corexit Having an Effect on Plants and Wildlife? The chemicals BP is now relying on to break up the steady flow of leaking oil from deep below the Gulf of Mexico could create a new set of environmental problems.

Even if the materials, called dispersants, are effective, BP has already bought up more than a third of the world's supply.